Crataegus rubribracteolata

J. B. Phipps & O’Kennon

J. Bot. Res. Inst. Texas 1: 1073, plates 6.1c, 7.3c, fig. 20. 2007.

Common names: Red bracteole hawthorn
Endemic
Treatment appears in FNA Volume 9. Treatment on page 520. Mentioned on page 516, 517, 521, 596.

Shrubs, erect, multistemmed in open, wide branching in shade, 20–30 dm. Stems: expanding bud-scales bright rufous-red; twigs: new growth color not recorded, appressed-pubescent, 1-year old mid brown, 2-years old dark redbrown, older gray or dark gray; thorns on twigs usually numerous, straight to slightly curved, 1-year old dark blackish brown, ± stout, 3.5–5.5 cm. Leaves: petiole length 30–35% blade, densely pubescent in adaxial sulcus, ± sessile-glandular; blade ± ovate to ovate-trullate, 4–7 cm, ± thin, base cuneate to broadly cuneate, lobes (4 or) 5 or 6 per side, sinuses moderately deep, max LII 25–33%, lobe apex acute to acuminate, margins with regular, acute teeth, often subacute mature, veins (5 or) 6 or 7 per side, apex acute to acuminate, abaxial surface glabrous except for sparse hairs along midvein proximally, adaxial ± densely scabrous-pubescent young (variably persistent to maturity). Inflorescences (6–) 8–12-flowered; branches ± tomentose; bracteoles abundant, deep orange-red or fading, narrow, margins densely sessile-glandular. Flowers 12–15 mm diam.; hypanthium ± tomentose or densely pubescent; sepals greenish or pale green, triangular, 3–5 mm, margins glandular-denticulate, apex ± red or paler red, abaxially glabrous, adaxially pubescent; stamens 10, anthers ivory or cream; styles 3 or 4. Pomes 3–10 in ± compact infructescences, red young, bright red or orange-scarlet in shade mature, ± ellipsoid to suborbicular, 9–13 mm tall, densely to sometimes sparsely pubescent; sepals appressed, 3–5 mm; pyrenes 3 or 4 (or 5), sides ± deeply concave.


Phenology: Flowering late May; fruiting late Aug–Sep.
Habitat: Thickets, sometimes under aspen
Elevation: 700–1100 m

Discussion

Crataegus rubribracteolata is restricted to the Cypress Hills and is common in suitable habitats. The record from Montana (Bear’s Paw Mountains, Hill County) is now considered dubious.

Crataegus rubribracteolata can be recognized by its upright habit when grown in full light. Surprisingly, it is most easily confused with C. ursopedensis (see key characters), not with C. sheridana. To C. ursopedensis, C. rubrobracteolata is similar in leaf shape, inflorescence, and indumentum; the mature leaves of C. rubribracteolata average smaller, except in some shade forms; both inflorescence form and indumentum are denser. It lacks the strikingly flabellate young leaves of C. ursopedensis, flowers significantly earlier, has smaller flowers, as well as different colored bracteoles. The two species are easily confused when these characteristics are not available; in fruit, the technical characteristics of pyrene and sepal orientation need careful observation.

Selected References

None.

Lower Taxa

None.
scabrous-pubescent +
0.8 cm8 mm <br />0.008 m <br /> (2.5 cm25 mm <br />0.025 m <br />) +
cream +  and ivory +
paler red +  and red +
pubescent +  and glabrous +
James B. Phipps +
J. B. Phipps & O’Kennon +
compound +  and simple +
opposite +  and alternate +
cuneate +  and broadly cuneate +
Crataegus sect. Macracanthae +
less ovate or rhombic-elliptic +  and rhombic-elliptic +
8 cm80 mm <br />0.08 m <br /> (12 cm120 mm <br />0.12 m <br />) +
less ovate +  and ovate-trullate +
4 cm40 mm <br />0.04 m <br /> (7 cm70 mm <br />0.07 m <br />) +
fading +, orange-red +  and deep +
bright rufous-red +
expanding +
adnate +  and distinct +
crowded +, scattered +  and alternate +
Red bracteole hawthorn +
Alta. +  and Sask. +
not +  and aggregated +
700–1100 m +
1.2 cm12 mm <br />0.012 m <br /> (1.5 cm15 mm <br />0.015 m <br />) +
unisexual +  and bisexual +
not +  and aggregated +
not +  and aggregated +
yellow +  and red or purplish +
0.6 cm6 mm <br />0.006 m <br /> (2 cm20 mm <br />0.02 m <br />) +
dark gray +, gray +, dark redbrown +, brown +  and appressed-pubescent +
older +, old +  and new +
tomentose +  and glabrous +
Thickets, sometimes under aspen +
pubescent +  and tomentose +
constricted +
0.2 cm2 mm <br />0.002 m <br /> (0.6 cm6 mm <br />0.006 m <br />) +
(6-)8-12-flowered +
crassinucellate +
deciduous +
craspedodromous +
entire +  and serrate +
stipitate-glandular +
glandular-denticulate +  and subacute +
inferior +  and superior +
biseriate +  and clustered +
collateral +  and basal +
0.8 cm8 mm <br />0.008 m <br /> (2.5 cm25 mm <br />0.025 m <br />) +
elliptic +  and circular +
0 (?) +  and 4 (?) +
free +  and distinct +
post-mature +
eglandular +  and glandular +
pubescent +
Flowering late May +  and fruiting late Aug–Sep. +
adnate +, free +, connate +  and distinct +
dark gray-brown +  and russet +
exfoliating +  and corrugated +
orange-scarlet +, bright red +  and red +
0.9 cm9 mm <br />0.009 m <br /> (1.3 cm13 mm <br />0.013 m <br />) +
mature +  and young +
less ellipsoid +  and suborbicular +
J. Bot. Res. Inst. Texas +
not arillate +
pale green +  and greenish +
persistent +
free +  and distinct +
glandular-denticulate +  and glandular-laciniate +
appressed +  and erect +
triangular +
0.3 cm3 mm <br />0.003 m <br /> (0.5 cm5 mm <br />0.005 m <br />) +
1-50-flowered +  and few-leaved +
eroded +  and pitted +
concave +
free +  and distinct +
branched +  and simple +
persistent +
distinct +
exsert +  and lateral +
elongate +
glabrous +  and tomentose +
Crataegus rubribracteolata +
Crataegus (sect. Macracanthae) ser. Macracanthae +
species +
6 cm60 mm <br />0.06 m <br /> (10 cm100 mm <br />0.1 m <br />) +
brown +  and dark blackish +
straight +  and slightly curved +
slender +
3.5 cm35 mm <br />0.035 m <br /> (5.5 cm55 mm <br />0.055 m <br />) +
inconspicuous +
less erect +  and oblique +
1 +  and several +
determinate +
7 +  and 6 +